You're more likely to get a hip flexor injury if you've had one in the past, you don't warm up properly before engaging in athletic activity, your muscles are already tight or stiff, or your muscles are weak from being overused. If, while exercising, you try to do too much at once in too short an amount of time, you can also put yourself at risk for a hip flexor injury.
This stretch opens the abductors and deeply opens the hips and lengthens the adductors while improving balance. Stand straight, holding the back of a chair at your left side. Lift your right knee into your chest, and grab hold of your foot with your right hand. Slowly straighten your leg up along your side, into a standing split. Keep your hand on your foot and lean your torso to the left. Hold this pose for 30 seconds before alternating sides.
It’s a common issue, says Prevention advisor Rob Danoff, director of family and emergency medicine residency programs at Aria Health in Philadelphia. "For people who sit a long time at work, the hip flexors and rotators become tight, and the gluteal muscles become weak," he says. "This combination negatively affects our ability to walk, maintain proper posture, and the stability of our spine."
If you can set aside time apart from your workouts, try Starrett’s couch stretch: In front of a couch or wall, sit on all fours. Place the shin of one leg parallel against the wall or couch, then bring one leg up into a kneeling position with your knee above your foot. Straighten your torso and fire your glute, as if to slide your two legs together. Hold for two minutes per side, contracting and releasing as you wish.
The only activity performed on a regular basis that fully extends the hip is walking and running. Hence as activity levels decrease so does the ability to extend the hip. This results in compensatory pelvic tilting and lumbar extension, with a reduction in the ability to accommodate uneven ground, negotiate obstacles, or attempt to change walking speed quickly. The compensatory pelvic tilt that accompanies tight hip flexors also predisposes the individual to postural problems and back pain. Hip stretches done on a regular basis can help you maintain extension range of motion and thereby improve function.

There’s much more happening behind the scenes when the hip flexes! Learning the attachments of the 11 hip flexor muscles is the best way to begin getting a handle on what’s happening when personal training clients complain of tight hip flexors or seem to have referred back pain from an imbalance in the muscles. You’re then able to design and suggest stretches and exercises that are specific to the issue at hand when you understand the form and function of these muscles. Here’s a few thoughts for you when doing that…

The more than 20 muscles that make up your hips are responsible for stabilizing your pelvis, moving your legs from side to side, and shortening to draw your knees toward your chest every time you sit down, run, jump or pedal, explains Kelly Moore, a certified yoga instructor and co-founder of Mindfuel Wellness, which brings health and wellness initiatives to companies throughout Chicago.